Answer: Cancer cells preferentially use aerobic glycolysis (glucose → lactate) even with oxygen present; this provides biosynthetic precursors for rapid growth and is exploited by PET scans (18F-FDG uptake).
- A Cancer cells are sometimes thought to use mainly oxidative phosphorylation for ATP production, generating little lactate output even when abundant oxygen is freely available to the tumour cell population
- B Cancer cells preferentially use aerobic glycolysis (glucose → lactate) even with oxygen present; this provides biosynthetic precursors for rapid growth and is exploited by PET scans (18F-FDG uptake)
- C Warburg effect is sometimes thought to mean cancer cells have no mitochondria, despite cancer cells in fact retaining largely functional mitochondria supporting biosynthetic roles alongside glycolysis
- D Cancer cells are sometimes thought to use mainly fatty acids as their dominant carbon and energy source, rather than relying primarily on aerobic glycolysis of glucose for rapid biosynthesis
Correct answer: B. Cancer cells preferentially use aerobic glycolysis (glucose → lactate) even with oxygen present; this provides biosynthetic precursors for rapid growth and is exploited by PET scans (18F-FDG uptake)
Explanation: Warburg effect (Otto Warburg, 1924): cancer cells use aerobic glycolysis preferentially even with adequate O<sub>2</sub>. Rationale: rapid ATP for immediate needs; provides biosynthetic precursors (pentose phosphate pathway for nucleotides, glycolytic intermediates for amino acids/lipids) to support rapid proliferation. Driven by oncogenes (MYC, RAS) and HIF-1. Exploited clinically: 18F-FDG PET (cancer cells take up more glucose, visible on PET scan).
The Plasmodium parasite needs both hosts: the female Anopheles mosquito injects sporozoites while biting (infecting the human liver and RBCs, causing the malaria fever cycle), then picks up gametocytes from an infected person's blood, completing the parasite's sexual stage inside the mosquito.
Concept context
Pathogens, infectious diseases, non-infectious diseases, drugs, cancer, and public health. High NEET importance.